1. Field of the Invention
The present invention relates to vehicle steering systems in which both front and rear road wheels are steerable.
2. Description of the Prior Art
A vehicle steering system is known that is constructed so that during low speed cornering of the vehicle the rear road wheels are turned in the direction opposite to the direction of turning of front road wheels and during high speed cornering the rear wheels and are turned in the same direction, the turning of the front wheels as is disclosed in U.S. Pat. No. 4,440,254 issued on Apr. 3, 1984 in the name of Shibahata et al and assigned to the same assignee as that of the subject application.
In such a steering system, during low speed running of the vehicle, a large angle of turning of the rear road wheels for a given steering effort on a steering wheel is desirable for efficiently reducing the radius of turning circle of the vehicle. However, during high speed running of the vehicle, a considerably smaller angle of turning of the rear road wheels for a given steering effort on the steering wheel is desirable for good stability of the vehicle.
No prior art steering system can satisfy this desire.